A bicycle includes a frame member that usually includes two triangular-shaped front and rear frame portions that have a common side. The rear frame portion usually includes two spaced and aligned rear sub-frame portions. A rear wheel is mounted for rotation between the two rear sub-frame portions.
The common side of the front and rear frame portions may support the mounting of a seat. An upper front corner of the front frame portion usually includes a cylindrical bore that removably and rotatably receives an upper part of a front fork member. Bearings may be located in the bore to facilitate rotation of the front fork member relative to the frame member. A bolt and a wedge-shaped member threadably mounted to the bolt are typically used to fix rotation of the front fork relative to a stem associated with handlebars of the bicycle.
A front wheel includes a front axle that is releasably attached to a lower end of the front fork member. For example, quick release fasteners and/or nuts may be used to attach the front axle to the front fork member. A rear wheel includes a rear axle that is releasably attached between lower rear corners of the rear sub-frame portions. Quick release fasteners and/or nuts may also be used to attach the rear axle to the rear sub-frame portions. A lower end of the common side of the front and rear frame portions includes a bore that receives bearings and a crank assembly. The crank assembly typically includes pedals that are connected by cranks to a chain wheel or front cog and a front derailleur. A chain connects the front chain wheel to a freewheel or rear cog and a rear derailleur, which are both associated with the rear wheel.
Front and rear brake levers are typically mounted on the handlebars and are connected by cables to front and rear brake assemblies. Each of the brake assemblies typically include a central mounting member. First and second arms with brake pads at distal ends thereof are pivotally connected to the center mounting member. A spring biases the first and second arms in an outwardly direction so that the brake pads do not contact the wheel when the brake levers are not depressed by the rider. When pressure is applied to the brake levers, the brake pads create friction which slows the wheels. This brake mechanism is typically exposed, which increases drag and reduces the esthetic appeal of the bicycle.
Since bicycles are human powered, it is advantageous to reduce the weight of the bicycle. Furthermore, the aerodynamic drag of the bicycle is preferably as a low as possible. In current bicycles, the design of the front fork member, the frame member and the brakes has not been sufficiently optimized. In other words, these structures have relatively poor aerodynamic characteristics, which increases drag. As a result, increased effort is required to sustain motion. In addition to reducing the aerodynamic drag of these structures, it would also be desirable to reduce the weight and manufacturing cost of these structures.